The present invention relates generally to eggs and, more particularly, to methods and apparatus for classifying eggs.
Discrimination between poultry eggs on the basis of some observable quality is a well-known and long-used practice in the poultry industry. xe2x80x9cCandlingxe2x80x9d is a common name for one such technique, a term which has its roots in the original practice of inspecting an egg using the light from a candle. As is known to those familiar with poultry eggs, although egg shells appear opaque under most lighting conditions, they are in reality somewhat translucent, and when placed in front of a direct light, the contents of the egg can be observed.
In most practices, the purpose of inspecting eggs, particularly xe2x80x9ctable eggsxe2x80x9d for human consumption, is to identify and then segregate those eggs which have a significant quantity of blood present, such eggs themselves sometimes being referred to as xe2x80x9cbloodsxe2x80x9d or xe2x80x9cblood eggs.xe2x80x9d These eggs are less than desirable from a consumer standpoint, making removal of them from any given group of eggs economically desirable.
Eggs which are to be hatched to live poultry also may be candled midway through embryonic development or later to identify infertile (xe2x80x9cclearxe2x80x9d) eggs and remove them from incubation to thereby increase available incubator space. Such inspection and removal is particularly useful in turkey hatcheries. Candlers also attempt to identify and remove xe2x80x9crottedxe2x80x9d and other dead eggs on the basis of their internal color. Unfortunately, conventional techniques may be difficult and unreliable, however, so that dead and rotted eggs may be inadvertently returned to incubation.
U.S. Pat. Nos. 4,955,728 and 4,914,672, both to Hebrank, describe a candling apparatus that uses infrared detectors and the infrared radiation emitted from an egg to distinguish live from infertile eggs.
U.S. Pat. No. 4,671,652 to van Asselt et al. describes a candling apparatus in which a plurality of light sources and corresponding light detectors are mounted in an array, and the eggs passed on a flat between the light sources and the light detectors.
In recent years, spectrographic techniques have been developed which irradiate eggs with particular frequencies of light which are sensitive to the presence of one or more of the characteristic components of blood (e.g., hemoglobin) to make a more accurate determination of whether or not the contents of the egg are indeed filled with blood or whether some other factor is interfering with the egg""s appearance or quality.
Other conventional techniques are used to inspect table eggs for the purpose of determining whether or not they are cracked. These techniques also use light sources and detectors because cracked eggs will often transmit more incident light towards a detector than will intact ones.
Recently, however, there have developed other reasons for distinguishing between eggs. One of these reasons is the advancements in techniques for treating poultry embryos with medications, nutrients, hormones or other beneficial substances while the embryos are still in the egg. Such techniques are quite advantageous compared to treatment of newly born chicks which often must be medicated, for example, by being hand inoculated one by one.
Injections of various substances into avian eggs are employed in the commercial poultry industry to decrease post-hatch mortality rates or increase the growth rates of the hatched bird. Similarly, the injection of virus into live eggs is utilized to propagate virus for use in vaccines. Examples of substances that have been used for, or proposed for, in ovo injection include vaccines, antibiotics and vitamins.
Examples of in ovo treatment substances and methods of in ovo injection are described in U.S. Pat. No. 4,458,630 to Sharma et al. and U.S. Pat. No. 5,028,421 to Fredericksen et al., the contents of which are incorporated by reference herein in their entireties. The selection of both the site and time of injection treatment can also impact the effectiveness of the injected substance, as well as the mortality rate of the injected eggs or treated embryos. See, e.g., U.S. Pat. No. 4,458,630 to Sharma et al., U.S. Pat. No. 4,681,063 to Hebrank, and U.S. Pat. No. 5,158,038 to Sheeks et al. U.S. Patents cited herein are hereby incorporated by reference herein in their entireties.
U.S. Pat. No. 3,616,262 to Coady et al. discloses a conveying apparatus for eggs that includes a candling station and an inoculation station. At the candling station, light is projected through the eggs and assessed by a human operator, who marks any eggs considered non-viable. Non-viable eggs are manually removed before the eggs are conveyed to the inoculating station.
Poultry eggs (hereinafter xe2x80x9ceggsxe2x80x9d) are typically inoculated on or about the eighteenth day of incubation. At such time, an egg may be one of several commonly recognized types. An egg may be a xe2x80x9clivexe2x80x9d egg, meaning that it has a viable embryo. FIG. 1A illustrates a live egg 1 at day one of incubation. FIG. 1B illustrates a live egg 1 at day twelve of incubation. The egg 1 has a somewhat narrow end in the vicinity represented at 1a as well as an oppositely disposed broadened end portion in the vicinity shown at 1b. In FIG. 1A, an embryo 2 is represented atop the yolk 3. The egg 1 contains an air cell 4 adjacent the broadened end 1b. As illustrated in FIG. 1B, the wings 5, legs 6, and beak 7 of a baby chick have developed.
An egg may be a xe2x80x9cclearxe2x80x9d or xe2x80x9cinfertilexe2x80x9d egg, meaning that it does not have an embryo. More particularly, a xe2x80x9cclearxe2x80x9d egg is an infertile egg that has not rotted. An egg may be an xe2x80x9cearly deadxe2x80x9d egg, meaning that it has an embryo which died at about one to five days old. An egg may be a xe2x80x9cmid-deadxe2x80x9d egg, meaning that it has an embryo which died at about five to fifteen days old. An egg may be a xe2x80x9clate-deadxe2x80x9d egg, meaning that it has an embryo which died at about fifteen to eighteen days old.
An egg may be a xe2x80x9crottedxe2x80x9d egg, meaning that the egg includes a rotted infertile yolk (for example, as a result of a crack in the egg""s shell) or, alternatively, a rotted, dead embryo. While an xe2x80x9cearly deadxe2x80x9d, xe2x80x9cmid-deadxe2x80x9d or xe2x80x9clate-dead eggxe2x80x9d may be a rotted egg, those terms as used herein refer to such eggs which have not rotted. Clear, early-dead, mid-dead, late-dead, and rotted eggs may also be categorized as xe2x80x9cnon-livexe2x80x9d eggs because they do not include a living embryo.
An egg may be an xe2x80x9cemptyxe2x80x9d egg, meaning that a substantial portion of the egg contents are missing, for example, where the egg shell has cracked and the egg material has leaked from the egg. Additionally, from the perspective of many egg detecting and identifying devices, an egg flat may be missing an egg at a particular location, in which case, this location may be termed a xe2x80x9cmissingxe2x80x9d egg. An egg may be placed in an egg flat such that it is an xe2x80x9cupside-downxe2x80x9d or xe2x80x9cinvertedxe2x80x9d egg, meaning that the egg has been placed in the flat such that the air cell thereof is mislocated, typically with the blunt end down.
Typically, eggs are held in flats on racks in carts for incubation in relatively large incubators. At a selected time, typically on the eighteenth day of age, a cart of eggs is removed from the incubator for the purposes of, ideally, separating out unfit eggs (namely, dead eggs, rotted eggs, empties, and clear eggs), inoculating the live eggs and transferring the eggs from the setting flats to the hatching baskets. Certain practical aspects of the incubation, handling and measuring processes may substantially diminish the accuracy of the methods and apparatus for distinguishing between live and dead eggs using conventional techniques.
While it is disadvantageous to discard live eggs, it is also disadvantageous to retain certain non-live eggs. In particular, if rotted or dead eggs are retained and inoculated, the inoculating needle may be contaminated, risking infection of subsequent live, healthy eggs. Furthermore, a treatment substance is wasted if injected in a non-live egg.
Furthermore, in some instances, it may be desirable to identify clear eggs (i.e., infertile, non-rotted eggs) and early dead eggs. While not suitable for producing broilers, these eggs may be useful for commercial food service or low grade food stock (e.g., dog food). The presence of bacterial contamination from rots decreases the value of this food stock.
In hatchery management, it is desirable to acquire information about the various types of eggs in each set of eggs. For example, it is desirable to know how many dead eggs are in a particular set of eggs. This information can be valuable because changes in the relative percentage of the various types of eggs are known to be caused by specific factors, such as improper incubator temperature settings, improper humidity, age and health of the flock of hens that laid the eggs, and the like. Unfortunately, current techniques for obtaining this information typically require destroying several hundred eggs from each set.
Although conventional tests for appearance and blood can discriminate to some extent between fertile and infertile eggs, there may be no reliable, automatic methods for distinguishing between live and dead eggs. Conventional candling techniques cannot effectively distinguish rotted eggs or late dead eggs from live eggs. Moreover, conventional candling techniques are generally unable to classify dead eggs as early dead, middle dead, or late dead. Therefore, there is a need for a highly reliable method of determining the condition of eggs, i.e., classifying eggs as live, dead (early, mid and late), clear, and/or rotted.
In view of the above discussion, embodiments of the present invention provide methods and apparatus that can non-invasively identify the present condition of eggs, namely, whether an egg is a live egg, a clear egg, an early dead egg, a middle dead egg, a late dead egg, a rotted egg, a cracked egg, and/or an inverted egg. According to embodiments of the present invention, a method of non-invasively identifying the present condition of eggs includes illuminating an egg with both visible and invisible light at wavelengths of between about three hundred nanometers and about eleven hundred nanometers (300 nm-1,100 nm). Light passing through an egg is received at a detector positioned such that a path of the received light does not pass through an aircell within the egg, except in the case of an inverted egg.
Preferably, a light source is positioned adjacent the end of an egg that is opposite the aircell, and a detector is positioned adjacent the egg at an angle of between about ten degrees and about ninety degrees (10xc2x0-90xc2x0) relative to a longitudinal axis of the egg. Moreover, the light source is preferably in contacting relationship with the egg such that light reflecting off of the egg shell is reduced. The light source does not necessarily need to be in contacting relationship with the egg. A collimated (i.e., focused) beam of light can also be utilized to reduce the amount of light reflected off of the egg shell.
The intensity of light passing through an egg is determined at a plurality of the visible and infrared wavelengths, and a spectrum that represents light intensity at selected ones of the visible and infrared wavelengths is generated. The generated spectrum then is compared with one or more spectra associated with a respective known egg condition to identify a present condition of the egg. For example, the generated spectrum may be compared with a respective spectrum associated with one or more of the following: live eggs, early dead eggs, middle dead eggs, late dead eggs, clear eggs, cracked eggs, rotted eggs, and/or inverted eggs.
According to embodiments of the present invention, an apparatus for processing eggs is provided that includes an identifier configured to determine a present condition of each of a plurality of eggs. The identifier includes a light source and a spectrometer. The light source illuminates each egg with light in both visible and infrared wavelengths between about three hundred nanometers and about eleven hundred nanometers (300 nm-1,100 nm). The spectrometer receives light passing through each egg and obtains intensity values of the received light at selected ones of the visible and infrared wavelengths. The spectrometer, or a processor in communication with the spectrometer, converts light intensity values for each egg into a respective spectrum and compares each generated spectrum with a plurality of spectra, wherein each of the spectra are associated with a respective known egg condition. A display may be provided that displays the identified present condition of each of the eggs.
According to additional embodiments of the present invention, an egg removal apparatus may be provided downstream from the identifier. The egg removal apparatus may be configured to remove eggs identified as live, dead, clear, cracked, rotted, or inverted. In addition, a plurality of injectors may be provided downstream from the identifier. Each injector may be configured to inject a substance into a respective egg identified as a live egg, and/or to remove material from a respective egg identified as a live egg.
The present invention may be advantageous because identification of live eggs versus non-live eggs (i.e., dead, rotted, cracked, clear, and inverted eggs) can be performed rapidly and more accurately than via conventional methods. Moreover, embodiments of the present invention are advantageous over conventional candling techniques which cannot effectively distinguish rotted eggs or late dead eggs from live eggs. As such, the number of improperly retained eggs (i.e., rotted and dead) which might otherwise contaminate inoculation needles can be reduced.
In addition, the possibility of discarding live eggs can be reduced. Accurate identification and removal of dead and rotted eggs may also provide a benefit during hatching of live eggs by removing a potential source of microbial contamination that could adversely affect chick health after hatch.
Identification methods and apparatus according to embodiments of the present invention may be used to further estimate the quantities or statistics of early dead, mid-dead, late-dead, rotted and empty eggs. Such information may be desired for the purposes of evaluating groups of eggs.